Recently, batteries are under development which have internal circuits such as a charge control circuit. In a case where such a battery is mounted on a wireless communication apparatus, the battery may adversely affect an antenna characteristic of the wireless communication apparatus. That is, when a high-frequency current passes through the circuit, the circuit operates like an antenna so that a radiation characteristic of the wireless communication apparatus is deteriorated. For example, as shown in FIG. 10, reduced is a gain in a frequency band of the antenna of the wireless communication apparatus.
FIG. 11 is a perspective view illustrating a schematic arrangement of a battery 900 according to a conventional technique. As illustrated in FIG. 11, the battery 900 has, in a case 902 having a battery terminal 906, a cell 904 and a circuit 908 which is electrically connected with the battery terminal 906. The circuit 908 is, e.g., a charge control circuit.
FIG. 12 is a cross-sectional view illustrating a schematic arrangement of a wireless communication apparatus 20 on which the battery 900 is mounted. As illustrated in FIG. 12, provided on a main body 21 of the wireless communication apparatus 20 are an antenna 22, a ground section 23 of a substrate of the main body 21, and an apparatus terminal 24. The apparatus terminal 24 and the battery terminal 906 constitute a battery connector.
In FIG. 12, arrows indicate a flow direction of the high-frequency current. As illustrated in FIG. 12, in the battery 900 according to the conventional technique, the circuit 908 operates like an antenna. That is, in a case where an electrical length of the circuit 908 is close to (1+2n)/4 wavelength (n: integer), a high-frequency current which resonates at the frequency of the wavelength passes through the circuit 908. This causes radiation from the circuit 908 so that an antenna characteristic of the antenna 22 is deteriorated.
As a technique for dissolving such a problem, Patent Literature 1 discloses such a technique that a conductive section of a battery and a ground section of a portable wireless apparatus are also electrically connected except via a battery terminal so that deterioration in antenna characteristic is suppressed.
FIG. 13 is a cross-sectional view illustrating a schematic arrangement of a wireless communication apparatus 30 disclosed in Patent Literature 1. As illustrated in FIG. 13, a battery 1000 which is mounted on the wireless communication apparatus 30 has: a battery terminal 1006, a circuit 1008 which is electrically connected with the battery terminal 1006; and a connecting section 1030 for connection with a ground section 33 of the wireless communication apparatus 30 except via the battery terminal 1006. Provided on a main body 31 of the wireless communication apparatus 30 are an antenna 32, an apparatus terminal 34 for connection with the battery terminal 1006, and a connecting section 35 for connection with the connecting section 1030. A ground line of the apparatus terminal 34 and the connecting section 35 are connected with the ground section 35.
Thus, the wireless communication apparatus 30 disclosed in Patent Literature 1 is different from the wireless communication apparatus 20 in that the connecting section 35 is provided for electrical connection with the circuit of the battery except via the battery terminal. Similarly, the battery 1000 disclosed in Patent Literature 1 is different from the battery 900 in that the connecting section 1030 is provided for electrical connection with the ground section of the wireless communication apparatus except via the battery terminal. These arrangements make it possible to suppress the deterioration in antenna characteristic of the antenna 32.
That is, as illustrated in FIG. 13, a high-frequency current (indicated by dashed arrows in FIG. 13) is passed in the battery 1000 from the connecting section 1030 to the battery terminal 1006 so that resonance is not caused in the circuit 1008 due to a high-frequency current (indicated by arrows in FIG. 13).